/*
 * Created on May 14, 2007
 * Created by Paul Gardner
 * Copyright (C) 2007 Aelitis, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 * 
 * AELITIS, SAS au capital de 63.529,40 euros
 * 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
 *
 */


package com.aelitis.azureus.util;

import org.gudy.azureus2.plugins.PluginInterface;
import org.gudy.azureus2.plugins.download.Download;
import org.gudy.azureus2.plugins.torrent.TorrentAttribute;
import org.gudy.azureus2.plugins.torrent.TorrentManager;

import com.aelitis.azureus.core.AzureusCore;

public class 
DownloadUtils 
{
	private static TorrentAttribute	ta_tracker_extensions;
	
	protected static void
	initialise(
		AzureusCore		core )
	{
		PluginInterface pi = core.getPluginManager().getDefaultPluginInterface();

		TorrentManager tm = pi.getTorrentManager();

		ta_tracker_extensions = tm.getAttribute( TorrentAttribute.TA_TRACKER_CLIENT_EXTENSIONS );
	}
	
	public static synchronized void
	addTrackerExtension(
		Download	download,
		String		extension_prefix,
		String		extension_value )
	{
		String	extension = "&" + extension_prefix + "=" + extension_value;
		
		String value = download.getAttribute( ta_tracker_extensions );

		if ( value != null ){

				// if already exists then bail
			
			if ( value.indexOf( extension ) != -1 ){

				return;
			}

				// if prefix exists then remove existing value
			
			if ( value.indexOf( extension_prefix ) != -1 ){

				String[] bits = value.split("&");

				value = "";

				for ( int i=0; i<bits.length; i++ ){

					String bit = bits[i].trim();

					if ( bit.length() == 0 ){

						continue;
					}

					if ( !bit.startsWith(extension_prefix.substring(1))){

						value += "&" + bit;
					}
				}
			}

			value += extension;

		}else{

			value = extension;
		}

		download.setAttribute( ta_tracker_extensions, value );
	}
}